Plastic water tight container

ABSTRACT

The present invention is an improved plastic container wherein the lid and bowl portions of the container fit together to form a water tight seal without the need for sealing gaskets. The plastic lid portion of the container includes a lid lip having a generally sinusoidal shape including a U shaped portion and a first inverted U shaped portion, the first inverted U shaped portion having a first wall, a first upper portion and an interior, a retaining bead projecting from the first wall into the interior of the first inverted U shaped portion, the U shaped portion having a second wall opposite the first wall of the first inverted U shaped portion. The bowl includes a bowl lip having a second inverted U shaped portion. The second inverted U shaped portion has third and fourth walls, a second upper portion and a lip edge. The third wall extends from a terminal end to the second upper portion, the fourth wall being contiguous with the bowl and the lip edge being positioned between the fourth wall and the top portion. The second inverted U shaped portion is dimensioned and configured to fit snugly within the interior of first inverted U shaped portion such that when the second inverted U-shaped portion is fully inserted into the first inverted U-shaped portion, a first seal is formed by the terminal end of the third wall bearing against a portion of the first wall immediately above the bead, a second seal is formed by a portion of the fourth wall bearing against a portion of the second wall and a third seal is formed by the lip edge bearing against the upper portion of the first inverted U-shaped portion.

FIELD OF THE INVENTION

The invention relates generally to injection molded plastic food containers.

BACKGROUND OF THE INVENTION

Inexpensive plastic containers have been manufactured for several decades. These containers generally include a lid section mated to a bowl section. Both the lid and bowl portions are generally thin walled products manufactured by using injection molding or thermoforming processes. These inexpensive bowls are an important part of the food service industry because they permit food products to be served to the public in a relatively secure container. Unfortunately, water tight containers are not simple to construct. The most effective way to ensure a secure water tight seal between the lid and the bowl portion of the container is to provide some sort of rubber sealing gasket at the intersection of lid and bowl. This greatly increases the cost of manufacturing the container. Alternatively, it is possible to design water proof plastic containers provided the plastic walls of the container are relatively thick and the lid and bowl are very closely mated to each other. This design approach, while effective, also results in an expensive container. An improved container having a water tight seal which does not require thick walled products or sealing gaskets is therefore desirable.

SUMMARY OF THE INVENTION

In accordance with one aspect of the present invention, there is provided an improved plastic container wherein the lid and bowl portions of the container fit together to form a water tight seal without the need for sealing gaskets. The plastic lid portion of the container includes a lid lip having a generally sinusoidal shape including a U shaped portion and a first inverted U shaped portion, the first inverted U shaped portion having a first wall, a first upper portion and an interior, a retaining bead projecting from the first wall into the interior of the first inverted U shaped portion, the U shaped portion having a second wall opposite the first wall of the first inverted U shaped portion. The bowl includes a bowl lip having a second inverted U shaped portion. The second inverted U shaped portion has third and fourth walls, a second upper portion and a lip edge. The third wall extends from a terminal end to the second upper portion, the fourth wall being contiguous with the bowl and the lip edge being positioned between the fourth wall and the top portion. The second inverted U shaped portion is dimensioned and configured to fit snugly within the interior of first inverted U shaped portion such that when the second inverted U-shaped portion is fully inserted into the first inverted U-shaped portion, a first seal is formed by the terminal end of the third wall bearing against a portion of the first wall immediately above the bead, a second seal is formed by a portion of the fourth wall bearing against a portion of the second wall and a third seal is formed by the lip edge bearing against the upper portion of the first inverted U-shaped portion.

With the foregoing in view, and other advantages as will become apparent to those skilled in the art to which this invention relates as this specification proceeds, the invention is herein described by reference to the accompanying drawings forming a part thereof, which includes a description of the preferred typical embodiment of the principles of the present invention.

DESCRIPTION OF THE DRAWINGS

FIG. 1. is a side view of the lid portion of a container made in accordance with the present invention.

FIG. 2. is a side view of the bowl portion of a container made in accordance with the present invention.

FIG. 3. is a cross sectional view of the lip portion of the bowl shown in FIG. 2.

FIG. 4 is a cross sectional view of the lip portion of the lid shown in FIG. 1.

FIG. 5 is a cross sectional view of the lip portions of the lid and bowl portions of the present invention being joined together.

FIG. 6 is a cross sectional view of the lip portions shown in FIG. 5 showing force vectors.

In the drawings like characters of reference indicate corresponding parts in the different figures.

DETAILED DESCRIPTION OF THE INVENTION

Referring firstly to FIGS. 1 and 2, the present invention is a plastic bowl having lid 12 and bowl 14. Lid 12 is made of a thin walled lid which is injection molded from a plastic such as polypropylene or the like. Lid 12 has bottom portion 26 and domed portion 28. Cleats 30 are formed on dome 28 and lip portion 16 is formed on bottom portion 26. Lip 16 extends all the way around the lid. Likewise, bowl portion 14 has bottom dome 20 with bottom 22 and top portion 24. Lip portion 18 extends all the way around top portion 24 of bowl portion 14.

Referring now to FIGS. 3 and 4, lip portion 16 is sinusoidal in shape having U-shaped portion 32 and first inverted U-shaped portion 34. Inverted U-shaped portion 34 has a first outer wall 36, interior 35 and top portion 37. Interior 39 is formed between first outer wall 36 and second wall 40 of U-shaped member 32. Bead 38 is formed on first wall 36 and projects into interior 35. Wall 36 is preferably sufficiently thin to permit it to deform slightly.

Lip portion 18 has second inverted U-shaped member 42. Second inverted U-shaped member 42 has third wall 44, top portion 46, terminal end 48 and fourth wall 50. Fourth wall 50 is contiguous with the rest of the bowl portion. Lip edge 15 is formed between top portion 46 and fourth wall 50 and is oriented towards bowl 14. Edge 15 is preferably relatively sharp, preferably just over about 90° or so.

Lip portion 18 is dimensioned to fit snugly with in interior 35 of first inverted U-shaped portion 34. Preferably, first inverted U-shaped portion 34 has an internal diameter measured between first wall 36 and second wall 40, while second inverted U-shaped portion has an exterior diameter measured by the exterior of third wall 44 and fourth wall 50. Preferably the internal diameter of first inverted U-shaped portion 34 is less than the external diameter of second inverted U-shaped portion 42. When the second inverted U-shaped portion 42 is fully inserted into interior 35 of first inverted U-shaped portion 34, terminal end 48 and portion 51 of first wall 36 bear against each other tightly to form seal A, portion 52 of wall 50 bears against portion 54 of second wall 40 with sufficient force to form seal B and edge 15 bears against top 37 of the first inverted U-shaped portion to form seal C. Preferably, wall 44 is dimensioned such that when fully inserted into the first inverted U-shaped portion, terminal end 48 is positioned immediately above bead 38, thereby preventing the second inverted U-shaped portion from slipping out of the first inverted U-shaped portion. Fist inverted U-shaped portion 34 and second inverted U-shaped portion 42 are dimensioned such that seal formed between walls 40 and 50 is positioned below the seal formed by walls 36 and 44.

As shown in FIG. 6, the outside diameter of portion 42 is sufficiently greater than the inside diameter of portion 34 such that lateral forces represented by vectors E and F are formed. Seals A and B are formed by the lateral forces represented by vectors E and F. Seals A and B are formed as substantially point like seals having relatively small surface areas, ensuring that the seals are tight and water tight. The relative sizes of portions 34 and 42 are such that transverse forces represented by vectors D and G are formed between portion 48 and edge 15. These forces are balanced and in opposite directions ensuring that portion 42 remains within portion 34. Edge 15, being relatively sharp, forms a tight seal C as it presses against the intersection of portions 37 and 40.

Seals A, B and C are point seals that are continuous all along lips 16 and 18, thereby ensuring a continuous seal between lid and bowl. Seals A, B and C are arranged to form a triangular arrangement illustrated by triangle H. Preferably, seals A, B and C are arranged such that triangle H is approximately an equilateral triangle to ensure that the three seals remain tight and secure. By having the three seals in an equilateral triangular arrangement, the lid remains very tightly sealed to the bowl and will resist being dislodged, even if the container drops.

A specific embodiment of the present invention peas been disclosed; however, several variations of the disclosed embodiment could be envisioned as within the scope of this invention. It is to be understood that the present invention is not limited to the embodiments described above, but encompasses any and all embodiments within the scope of the following claims. 

Therefore, what is claimed is:
 1. A plastic container comprising: a lid including a lid lip having a generally sinusoidal shape including a U shaped portion and a first inverted U shaped portion, the first inverted U shaped portion having a first wall, a first upper portion and an interior, a retaining bead projecting from the first wall into the interior of the first inverted U shaped portion, the U shaped portion having a second wall opposite the first wall of the first inverted U shaped portion; a bowl including a bowl lip having a second inverted U shaped portion, the second inverted U shaped portion having a third and fourth wall, a second upper portion and a lip edge, the third wall extending from a terminal end to the second upper portion, the fourth wall being contiguous with the bowl and the lip edge being positioned between the fourth wall and the top portion; the second inverted U shaped portion being dimensioned and configured to fit snugly within the interior of first inverted U shaped portion, the first and second inverted U shaped portions being further dimensioned such that when the second inverted U-shaped portion is fully inserted into the first inverted U-shaped portion, a first seal is formed by the terminal end of the third wall bearing against a portion of the first wall immediately above the bead and a second seal is formed by a portion of the fourth wall bearing against a portion of the second wall and a third seal is formed by the lip edge bearing against the upper portion of the first inverted U-shaped portion.
 2. The container of claim 1 wherein the first seal is formed above the second seal.
 3. The container of claim 1 wherein the lip edge is relatively square.
 4. The container of claim 1 wherein the interior of the first inverted U-shaped portion has an internal diameter measured between the first wall and the second wall and wherein the second inverted U-shaped portion has an exterior diameter measured between the terminal end and the fourth wall, the exterior diameter of the second inverted U-Shaped portion being slightly greater than the interior diameter of the first inverted U-shaped portion.
 5. The container of claim 3 wherein the lip edge is just over 90°.
 6. The container of claim 1 wherein the first, second and third seals are arranged in a triangular arrangement which is approximately equilateral.
 7. A container comprising: a lid including a lid lip having a generally sinusoidal shape including a U shaped portion and a first inverted U shaped portion, the first inverted U shaped portion having a first wall, a first upper portion and an interior, a retaining bead projecting from the first wall into the interior of the first inverted U shaped portion, the U shaped portion having a second wall opposite the first wall of the first inverted U shaped portion, the second wall being much thicker than then first wall; a bowl including a bowl lip having a second inverted U shaped portion, the second inverted U shaped portion having a third and fourth wall, a second upper portion and a lip edge, the third wall extending from a terminal end to the second upper portion, the fourth wall being contiguous with the bowl, the lip edge being formed between the fourth wall and the second upper portion, the lip edge being relatively square; the second inverted U-shaped portion having an external diameter measured between the terminal end and the fourth wall and the first inverted U-shaped portion having an internal diameter measured from the first wall immediately above the bead to the second wall, the outer diameter of the second inverted U-shaped portion and the inner diameter of the first inverted U-shaped portion being selected such that the second inverted U-shaped portion fits snugly within the interior of first inverted U shaped portion, the internal and external diameters of the first and second inverted U-shaped portions, respectively, being further selected such that when the second inverted U-shaped portion is fully inserted into the first inverted U-shaped portion, a first seal is formed by the terminal end of the third wall bearing against a portion of the first wall immediately above the bead and a second seal is formed by a portion of the fourth wall bearing against a portion of the second wall and a third seal is formed by the lip edge bearing against the upper portion of the first inverted U-shaped portion.
 8. The container of claim 7 the first, second and third seals are in a triangular arrangement, the triangular arrangement being substantially equilateral. 